Tui hot spots were Otari-Wilton, Aro Valley, Brooklyn and Ngaio, though the population was increasing across the city, she said.

The population of tui and other birds are monitored in autumn and spring, using a series of surveys across Wellington reserves. Bird songs are recorded for five minutes by volunteers and then analysed.

Since 2001, the total number of tui heard jumped from 68 to 510.

The tui is one of our most distinctive birds with its white tuft under the throat and sleek dark green-blue plumage.

Ms Bill said tui were probably spreading from the Karori Sanctuary and naturally recolonising the city.

Other factors in the rise of tui included efforts to control possums and other pests, and more native trees being planted in gardens. “It’s hard to pin it down to any one thing.”

The surveys showed other bird species including kaka and saddleback were also on the rise. Ms Bill said the key to keeping tui numbers increasing was to provide more food and cut predator numbers.

Sanctuary spokesman Alan Dicks said it had received reports of tui in suburbs where they had not been seen for years, such as Miramar. “We should all be extremely proud.”

However, the return of the tui has not been welcomed by all Wellingtonians. In January it was revealed Karori Sanctuary had received complaints from people kept awake by the birds’ raucous singing.

Mr Dicks said there were no complaints so far this spring. “Hopefully … last summer was enough to make people appreciate what a good thing we’ve got here.”

15 rare Wellington green geckos, seven of which have spent the last twelve months on ‘sabbatical’ at the city’s Karori Sanctuary, are being released on the island on Friday 15 November as part of an annual translocation programme – the largest to date.

DOC first began translocating green geckos to the island sanctuary in 2006 to create a self-sustaining population on this predator-free island. They have been working with local lizard breeders to ensure a genetically diverse supply of geckos for release on a yearly basis. This year, 16 lucky local school children with a special interest in conservation have been chosen to take part in the release.

‘Establishing a safe population on Matiu/Somes will help ensure survival’, said DOC biodiversity ranger Brent Tandy.

Local lizard enthusiasts and conservation projects like Karori Sanctuary play a critical support role for DOC’s gecko recovery programme in terms of both advocacy and breeding. One year old animals are taken to the Sanctuary for display in a special gecko enclosure before being released on the island at two years old.

A big jump in the number of tui visiting Hamilton is predicted next year as the impact of a successful breeding project kicks in.

Environment Waikato expects a bumper tui breeding season at its Hamilton Halo project sites this spring, thanks to a highly successful winter of pest control operations. This is expected to produce results by next winter.

EW aims to attract more tui to the city by wiping out the birds’ two main predators – ship rats and possums – at breeding sites near the city.

It is currently controlling the pests at one Whatawhata site and two sites near Cambridge, Maungakawa Scenic Reserve and Te Miro Reserve. There is around 850 hectares of native bush under protection.

The regional council devised a special pest control programme to kill the rats using more than 1300 bait stations across the three sites.

Pest control took place in August and September, before the October tui breeding season.

EW councillor Paula Southgate said the results of a recent rat census were excellent, with only 2.2 per cent of the 225 tracking tunnels registering rat footprints, compared with up to 41 per cent before pest control.Estimates from Landcare Research were that nesting success could increase from around 25 per cent to 75 per cent.

There were also reports that native seedlings were flourishing on the forest floor without possums and rats around. Other native birds, such as kereru and bellbirds, are also expected to benefit from the programme.